#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
int Fibonacci(int n)
{
	if (n <= 2) {
		return 1;
	}else{
		return Fibonacci(n-1)+Fibonacci(n-2);
	}
}
int main() {
	/*int a[100];
	a[0] = 1;
	a[1] = 1;
	int n = 0;
	scanf("%d", &n);
	for (int i = 2; i < n; i++) {
		a[i] = a[i - 1] + a[i - 2];
	}
	printf("%d", a[n - 1]);*/
	int n = 0;
	scanf("%d", &n);
	printf("%d", Fibonacci(n));
	return 0;
}